Pavement crack cleaner

ABSTRACT

Devices for cleaning and preparing pavement cracks for sealing are disclosed. An example device comprises a wire brush assembly for removal of mid and large-sized debris, an air blaster for removal of fine-grained particulate, a heat lance, and a vacuum for controlled removal of debris and particulates. The example device would also have means for attachment to an air compressor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.61/470,547 entitled “Pavement crack cleaner for sealing,” filed Apr. 1,2011, which is incorporated herein by reference in its entirety for allpurposes.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under National Academyof Sciences grant number NCHRP-159. The government has certain rights inthe invention.

TECHNICAL FIELD

The present disclosure relates generally to cleaning and preparingcracks in pavement for sealing. More specifically, the presentdisclosure pertains to a device for efficiently and effectively cleaningpavement cracks of debris and de-icing chemicals in preparation forsealing of the pavement cracks.

BACKGROUND OF THE INVENTION

Flexible and rigid pavement joints and cracks are sealed or filled tomitigate further damage caused by the infiltration of water and foreigndebris. Crack sealing is generally recommended for 5 to 19 mm sizecracks, and can be utilized for cracks outside this range as well. Thetraditional procedures for preparing roadway joints and cracks forsealing and/or filling are either largely ineffective, labor intensive,or dangerous.

Air blasting is the most common means of pavement crack preparation.This method effectively expels voids of dust and relatively loosecontaminants. Should the crack possess any level of moisture it isrecommended that hot air blasting be utilized. However, air blasting isnot an effective means of cleaning out vegetation and large debris, aswell as the thin layer of de-icing chemicals that often coat thepavement of cold weather prone regions. Lastly, sealants and fillersrequire the surface of the pavement to be at least 40° F. for properbonding; as cracks are more often sealed within the freeze-thaw periodof winter, air blasting is not a recommended means of sole crackpreparation.

Hot air blasting solves many of the cold weather drawbacks that areassociated with the above procedure. Hot air blasting typically uses acompressed air heat lance that introduces gas and combustion to thecompressed air to provide a hot jet of air to the treated area. However,hot air blasting introduces other problems. Extreme caution must betaken to ensure the pavement is not overheated, which will result in theasphalt binder becoming brittle and leading to premature failure. Careshould also be taken to never allow for direct flame methods to be usedas the charring effect will lead to a soot residue and cause poorinitial bonding. It is not difficult to find such direct flame problemsin the current practices. In addition, hot air blasting does not cleande-icing chemicals remaining in and out of the cracks. Furthermore,propane regulators are often frozen in cold weather, thus delaying thesealing process.

Sandblasting is noted as an efficient method of removing the de-icingchemicals often present in roadway cracks. However, there are severaldrawbacks to the sandblasting method of crack preparation. The firstproblem is that it includes two operators: one for the sand blasting,and one for cleaning out the sand left behind. Sandblasting also has anumber of environmental and health concerns associated with it.

Although routing is a better approach than the methods above forcleaning cracks, it is not a solution for complete preparation for cracksealing. Routing only excavates narrow cracks and still leaves de-icingchemicals on both sides of the crack surface. The surface preparation isvery important for better bonding between surface and sealing material.Also, routing which generally uses a ⅜″ carbide-tipped rotary impact bitis not effective for wider cracks to clean de-icing chemicals in cracksunless multiple routing paths are used. Furthermore, many groupshesitate to rout cracks because the routing equipment is very heavy andmakes it difficult to follow cracks unless cracks are straight. It oftenresults in creation of another crack while routing random cracks.Pulling such heavy equipment downhill or on a windy day often puts theoperator in dangerous situations as well.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a mechanical device used toeffectively clean pavement cracks and the surrounding area, and therebyprepare pavement cracks and joints for sealing or filling. The device iscapable of removing dirt, loose debris, and de-icing chemicals. Thedevice is a highly customizable mechanism capable of being outfittedwith a pneumatically driven rotary wire brush assembly, pavement routingassembly, vacuum, air blaster, or heat lance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a pavement crack cleaner device with arouter attachment and air blaster.

FIG. 2 is a schematic view of the wire brush assembly with an airblaster.

FIG. 3 is a schematic view with a masonry bit and an air blaster.

FIG. 4 is a schematic view of the router attachment and air blaster fromthe right side of the device.

FIG. 5 is a schematic view of the pavement crack cleaner device as inFIG. 1, with the addition of the heat lance.

FIG. 6 is a cross-sectional view of the heat lance attached to thepavement crack cleaner device.

FIG. 7 is the pavement crack cleaner device of FIG. 5 with the additionof a vacuum component.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic view showing one of the embodiments of theinvention. The lever near the handle at the top of the device allows theuser to control the air flow rate to the air blaster. The control switchjust below the handle acts to split the air flow between the air blasterand the pneumatically powered motor. The motor is located within thehousing just above the guard cover. The guard cover is the semi-circlein the drawing above the pavement router which acts to prevent debrisfrom flying up or to the left of the device as it operates. The primaryair blaster nozzle is positioned behind the pavement router.

FIG. 2 is a close-up view of an embodiment showing the wire brushassembly instead of the pavement router. All other aspects of thisembodiment are identical to the embodiment in FIG. 1.

FIG. 3 is a close-up view of an embodiment showing a masonry bit insteadof the pavement router. All other aspects of this embodiment areidentical to the embodiment in FIG. 1.

FIG. 4 is a schematic view of the embodiment in FIG. 1, from theopposite side of the device.

FIG. 5 is a schematic view of the embodiment in FIG. 1 with the additionof an electrically-powered heat lance. The heat lance is positioned justabove the guard cover and has an electrical power cord that is attachedto the shaft of the device.

FIG. 6 is contains a cross-sectional view of the heat lance, displayingthe heat coils internal to the heat lance.

FIG. 7 is a schematic view of the embodiment in FIG. 5 with the additionof a vacuum component. The vacuum intake is directly behind the routerand air nozzle, and acts to suck in particles and debris cleaned fromthe pavement crack.

One contemplated embodiment of this device consists of a pneumaticallydriven wire brush assembly and air blaster. The wire brush assembly isused to clean the mid- to large-sized debris, old sealed material, andvegetation from the pavement cracks, with the air blaster following thewire brush assembly to further expel fine grained particulate. The wirebrush assembly ideally is made from steel and/or aluminum, but othermaterials could work just as well. Different sizes of steel wire brushescan be used depending on the diameter or width of the crack needing tobe cleaned. The compressed air blaster should ideally have a minimumpressure of 100 lb/in², but the device would still be functional atlower pressures. The minimum ideal flow rate of the compressor should be150 ft³/min, but the device would still function at lower flow rates. Asecondary air nozzle either with a direction-adjustable air hose or astraight air wand may also be attached to the device. This can be usedwhen cleaning debris created on the pavement surface.

The device could additionally comprise a heat lance, and the ability toretrofit the device with a single router bit which is interchangeablewith the wire brush assembly. The ability to add an optional heat lanceis important as pavement cracking typically occurs in moist or coldclimates. The heat lance will allow pavement crews to adequately heatthe pavement crack to the recommended 40° F. while removing anyadditional moisture in the crack, both of which are critical toobtaining proper material adhesion. The temperature of the heat lancemust not exceed 930° F. to prevent overheating of the pavement. Heatlances that run on propane gas are the only option currently availablefor pavement crack cleaning. The present invention could comprise a heatlance powered by propane gas, or alternatively by electricity. Manystreet maintenance trucks already have electrical generators, whichcould be used to supply the electricity for the heat lance.Alternatively, a separate electrical generator could be used to powerthe heat lance.

Many pavement cracks will not sufficiently allow for the penetration ofa stiff bristled wire brush, and routing must take place. The presentdevice can allow for the ability to interchange the wire brush assemblywith pavement routing bits. In order to interchange the wire brushassembly with the pavement routing bit, the guard cover is removed andthe nut holding the wire brush assembly to the device is removed. Thewire brush assembly can then be removed. The router bit can then beinstalled by inserting a bushing in the router bit since the size of therouter bit is different from that of the wire brush assembly. The nut isthen placed back on to hold the router bit in place, and finally theguard cover is replaced. The routing bit should be capable of routingwidths of 12 mm to 38 mm, and routing to a depth of 19 mm. The devicecould additionally comprise a vacuum component for control and disposalof the debris and particulates being cleaned from the pavement crack.The vacuum component is positioned behind the air blaster to catch theexpelled particulates and debris. The vacuum suction should be powerfulenough to capture an adequate amount of the particulates and debris. Anindustrial vacuum with an 110V power supply and suction rate of 18ft³/min at 100 lb/in² would be powerful enough to accomplish this task.

Another embodiment would involve using a masonry blade unit in place ofthe wire brush assembly or pavement router. The masonry blade unit canbe used for many applications, including pothole repair. The masonryblade unit is attached to the device in the same manner as the wirebrush assembly and pavement router.

The affordability of this device is a benefit over the currentlyexisting options for pavement crack cleaning. Purchasing a newcommercially available gas-powered pavement router, gas combustion heatlance, and crack cleaning vacuum system will cost maintenance agencies$10,000, $3500, and $60,000 respectively. On the other hand, thisinvention could conceivably incorporate all three of the previouslymentioned units at a small fraction of their total costs. This isaccomplished by using pneumatically powered components, which hasconsiderable cost savings and safety benefits over gas-poweredcomponents. The combination of the wire brush assembly and air blastershould act to remove deicing chemicals, which is imperative to thesealed cracks lasting as long as possible. The combination of multipledevices into a single device also means less labor power required toclean the pavement crack, turning a three or four person job intosomething that can be accomplished by a single person.

The safety benefits of this device cannot be overlooked. The new devicewill have the ability to largely replace the use of sandblasting andcompressed gas heat lancing. The abrasion by wire brush or simply usingthe router bit to open up existing cracks will eliminate the health andenvironmental concerns associated with sandblasting. Additionally, theuse of an electrically powered heat lance as a means of warming pavementcracks will eliminate the many safety considerations that must beaddressed when utilizing flammable gas. The cover guard also acts toprotect the operator from flying particulates and debris, and eitherguides the debris into the vacuum in certain embodiments, or else downor to the side away from the device and operator in other embodiments.

There is a clear benefit in regard to mechanical simplicity. Theproposed device is powered by pneumatic means. A person of ordinaryskill in the art will understand pneumatically powered to mean usingcompressed air to power a device. This allows for a decrease inmaintenance cost due to the simplicity of air driven motors, rather thanthe traditional gasoline engines used to power the portable rotarybrushes and routers. Additionally, the need for hauling combustible fuelis eliminated. The device will be easily attached to current airblasting devices, or maintenance trucks equipped with air compressors,making the upgrade costs as minimal as possible. Most maintenance truckscurrently have a one-inch Chicago fitting for air hose connection. Ahose can be connected to an air compressor on a maintenance truck, andthen be run to the device. The air supply would be split, with some airbeing used for the air blaster component, and some air being used tooperate the pneumatically powered motor of the device.

In addition, it is expected that this device will be used on a higherpercentage of cracks, yielding an increase in preventative maintenanceand a decrease in new construction costs by formulating a more efficientway of cleaning joints and cracks, including removal of de-icingchemicals. The current state of the art does not effectively removede-icing chemicals. The combination of the wire brush assembly with theair blaster allows the present device to remove the chemicals, resultingin significantly more effective crack seals. Preventative maintenance isgenerally considered to be much more cost effective than rehabilitationand reconstruction. Furthermore, utilizing versatile effective means ofcrack and joint preparation will undoubtedly lead to an increase inoverall quality. This upgrade in quality will promote an increase in theuseful life of pavements, and postpone the allocation of valuable taxrevenue towards the rehabilitation or new construction of existingroadways.

The device includes a heavy-duty pneumatic motor to power the variouscomponents of the device. The motor could be 1.25 hp (950 W) with amaximum of 7,500 rpm. Motors with similar or more powerfulspecifications would also work. Also an electrical heat lance workingwith either 110V or 220V can be attached to the device to generate hotair. Another configuration of the device will include an attachablevacuum system. The suction compartment will be attached behind the wirebrushing/routing mechanism in this configuration, as can be seen in FIG.7. The device has the correct air pressure and supply to ensure thevarious working components are appropriately powered. The air pressureand supply can be adjusted depending on the requirements of a specificpavement crack.

The heat lance attached to the device can be either gas powered orelectrically powered. In either case, the heat lance should be capableof heating the pavement crack to 40° F. The heat will be delivered tothe crack pneumatically.

The addition of a vacuum component is very important to meet a number ofstate's environmental protocols, and to make it safer for the pavementcrew and surrounding traffic. The vacuum component should be powerfulenough to capture large-sized debris in addition to fine particulatecreated from brushing and routing processes.

The present device maintains a high level of innovation for three keyreasons: 1) the device can be completely powered by pneumatic power, apower source standard on most maintenance trucks and already used withinthe typical joint and crack sealing process; 2) the device can customizeup to four tasks in one pass: routing and brushing, air blasting,vacuuming, and warming the pavement; and 3) the proposed device is notonly lower-cost, but also lighter and easier to maneuver on cracks andjoints compared to pushing and rotating a heavy walk-behind device.

1. A device for cleaning pavement cracks comprising a wire brushassembly and an air blaster.
 2. The device of claim 1, furthercomprising a heat lance.
 3. The device of claim 2, wherein said heatlance is electrically powered.
 4. The device of claim 1, furthercomprising a single router bit capable of being interchanged with thewire brush assembly.
 5. The device of claim 1, further comprising avacuum component.
 6. The device of claim 1, further comprising apneumatic motor.
 7. The device of claim 1, further comprising a means ofattachment to an external pneumatic power source.
 8. A device forcleaning pavement cracks comprising a single router bit and an airblaster.
 9. The device of claim 8, further comprising a heat lance. 10.The device of claim 9, wherein said heat lance is electrically powered.11. The device of claim 8 further comprising a wire brush assemblycapable of being interchanged with the single router bit.
 12. The deviceof claim 8, further comprising a vacuum component.
 13. The device ofclaim 8, further comprising a pneumatic motor.
 14. The device of claim8, further comprising a means of attachment to an external pneumaticpower source.